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Electrochemical Stability (electrochemical + stability)
Selected AbstractsChemInform Abstract: Ru-Pyrochlores: Compositional Tuning for Electrochemical Stability as Cathode Materials for IT-SOFCs.CHEMINFORM, Issue 10 2009G. Ehora Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Acenaphtho[1,,2- c]phosphole P -Oxide: A Phosphole,Naphthalene ,-Conjugated System with High Electron MobilityCHEMISTRY - A EUROPEAN JOURNAL, Issue 39 2009Arihiro Saito One order of magnitude: Naphthalene- and acenaphthene-fused phosphole P -oxides (see figure) are shown to have reasonably high thermal and electrochemical stabilities and electron-accepting ability. The electron mobility of the naphthalene-fused phosphole P -oxide is about one order higher than that of tris(8-hydroxyquinoline)aluminium(III) Alq3 at any given electric field. [source] Solvent-Free Ionic Liquid Electrolytes for Mesoscopic Dye-Sensitized Solar CellsADVANCED FUNCTIONAL MATERIALS, Issue 14 2009Shaik M. Zakeeruddin Abstract Ionic liquids have been identified as a new class of solvent that offers opportunities to move away from the traditional solvents. The physical-chemical properties of ionic liquids can be tuned and controlled by tailoring their structures. The typical properties of ionic liquids, such as non-volatility, electrochemical stability and high conductivity, render them attractive as electrolytes for dye-sensitized solar cells. However, the high viscosity of ionic liquids leads to mass transport limitations on the photocurrents in the solar cells at full sunlight intensity, but the contribution of a Grotthous-type exchange mechanism in these viscous electrolytes helps to alleviate these diffusion problems. This article discusses recent developments in the field of high-performance dye-sensitized solar cells with ionic liquid-based electrolytes and their characterization by electrochemical impedance analysis. [source] Synthesis of Oxygen-Containing Spirobipyrrolidinium Salts for High Conductivity Room Temperature Ionic LiquidsHELVETICA CHIMICA ACTA, Issue 8 2009Seiichiro Higashiya Abstract Synthesis of ionic liquids (IL) based on oxygen-containing spirobipyrrolidinium salts with BF4, BF3C2F5, and NTf2 as counterions was undertaken. Their physical and electrochemical properties were evaluated for suitability for Room Temperature Ionic Liquids (RTIL) application. Reduction in melting point occurred upon exchange of C(2) by an O-atom of spirobipyrrolidinium, without sacrificing the electrochemical stability; while introduction of alkyl groups between the N- and O-atoms led to incorporation of asymmetry, and hence reduced the melting points, and viscosity. [source] Nanoscale Organic Hybrid ElectrolytesADVANCED MATERIALS, Issue 33 2010Jennifer L. Nugent Nanoscale organic hybrid electrolytes are composed of organic-inorganic hybrid nanostructures, each with a metal oxide or metallic nanoparticle core densely grafted with an ion-conducting polyethylene glycol corona - doped with lithium salt. These materials form novel solvent-free hybrid electrolytes that are particle-rich, soft glasses at room temperature ; yet manifest high ionic conductivity and good electrochemical stability above 5V. [source] Effects of organophilic clay on the solvent-maintaining capability, dimensional stability, and electrochemical properties of gel poly(vinylidene fluoride) nanocomposite electrolytesJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 22 2002H. J. Liu Abstract Four quaternary alkyl ammonium salts were used in an organophilic procedure, performed on montmorillonite clay, and resulted in intercalation in dimethylformamide (DMF) or ethylene carbonate (EC)/propylene carbonate (PC) as a cosolvent between poly(vinylidene fluoride) (PVdF) and the organophilic clay. An examination using X-ray diffraction revealed that PVdF entered galleries of montmorillonite clay, and it exhibited exfoliation and intercalation phenomena when it was analyzed with transmission electron microscopy. Gel PVdF nanocomposite electrolyte materials were successfully prepared by the addition of the appropriate percentages of DMF or PC/EC as a cosolvent, organophilic clay, and lithium perchlorate to PVdF. The maximum ionic conductivity was 1.03 × 10,2 S/cm, and the materials exhibited better film formation, solvent-maintaining capability, and dimensional stability than electrolyte films without added organophilic clays. The results of cyclic voltammetry testing showed that the addition of the organophilic clays significantly enhanced the electrochemical stability of the polymer electrolyte system. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3873,3882, 2002 [source] Electrochemical deposition of Pt nanoparticles on diamond substratesPHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 9 2009Jingping Hu Abstract Platinum nanoparticles were deposited on polished smooth, as-grown large grain and small grain diamond substrates by a potentiostatic method. The influence of deposition potential and the morphology of BDD substrates were studied. A progressive nucleation along with spherical clusters was observed on smooth BDD electrode, accompanied with a heterogeneous segregation of platinum on diamond facets of higher electrochemical activities and a weak binding to the substrate. In contrast, an instantaneous nucleation was observed on as-grown small grain and large grain BDD electrodes, with a dendritic microstructure and a much larger specific active area. The platinum decorated as-grown smaller grain BDD electrodes show a much better electrochemical stability than the other electrodes investigated. [source] Electrochemical stabilization of crystalline silicon with aromatic self-assembled monolayers in aqueous electrolytesPHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 14 2005Murat Tutus Abstract We report stable chemical engineering of hydrogen-terminated Si[111] surfaces in aqueous electrolytes by electrochemical grafting of aromatic monolayers. The topography and free energy of the engineered surface obtained from AFM and contact angle measurements confirmed homogeneous coating of the surface with a monolayer. Grafting of monolayers actually resulted in a clear suppression of the surface defect densities, demonstrated by photoluminescence lifetime. Changes in the surface chemical identities after grafting and post-treatments were followed by X-ray photoelectron spectroscopy (XPS). The electrochemical stability in aqueous electrolytes was assessed by impedance spectroscopy, revealing an improved stabilization of the Si/electrolyte interface by the grafted monomolecular film. This protocol was further applied for another aromatic compound, where the impact of 4-substituent functions could clearly be detected by photovoltage measurements. The chemical and electrochemical stability achieved here is promising for the successive deposition of biocompatible polymer films and lipid membranes. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Novel microporous poly(vinylidene fluoride)- graft -poly(tert -butyl acrylate) electrolytes for secondary lithium batteriesPOLYMER INTERNATIONAL, Issue 11 2008M Abdul Kader Abstract BACKGROUND: Much interest has recently been shown in improving the performance of lithium-ion polymer batteries with gel polymer electrolytes (GPEs) due to a rapid expansion in industrial demand. Novel GPEs based on poly(vinylidene fluoride)- graft -poly(tert -butyl acrylate) (PVDF- g - tBA) microporous mats are suggested in this study. RESULTS: Microfibrous polymer electrolytes were prepared using electrospinning and characterized for extent of grafting, morphology, crystallinity, electrochemical stability, ionic conductivity, interfacial resistance and cell cycleability. The degree of crystallinity was lower for tBA-grafted PVDF mats than that of neat PVDF. The PVDF- g - tBA showed an improvement in the ionic conductivity, electrochemical stability, interfacial resistance and cyclic performance. CONCLUSION: The tBA-grafted PVDF microporous electrolytes are promising candidates for enhancing the performance of lithium-ion polymer batteries. Copyright © 2008 Society of Chemical Industry [source] Tetraalkylammonium Salts of Weakly Coordinating Aluminates: Ionic Liquids, Materials for Electrochemical Applications and Useful Compounds for Anion InvestigationCHEMISTRY - A EUROPEAN JOURNAL, Issue 8 2009Ines Raabe Dr. Abstract Weak and robust? Tetraalkylammonium salts of weakly coordinating fluorinated alkoxyaluminates are easily accessible, chemically robust materials that show interesting physico-chemical properties like low melting points, high electrochemical stability and electric conductivity in weakly polar solvents such as CH2Cl2, Ph-F and toluene. In this study, we investigated the tetraalkylammonium salts of the weakly coordinating fluorinated alkoxyaluminates [pftb], ([Al(O(C(CF3)3)4],), [hfip], ([Al(OC(H)(CF3)2)4],) and [hftb], ([Al(OC(CH3)(CF3)2)4],) in order to obtain information on their undisturbed spectral and structural properties, as well as to study their electrochemical behavior (i.e., conductivities in non-polar solvents and electrochemical windows). Several of the compounds qualify as ionic liquids with melting points as low as 42,°C for [NBu4]+[hfip],. Simple and almost quantitative metathesis reactions yielding these materials in high purity were developed. These [NR4]+ salts serve as model compounds for undisturbed anions and their vibrational spectra,together with simulated spectra based on quantum chemical DFT calculations,were used for the clear assignment of the anion bands. Besides, the ion volumes of the anions (Vion([pftb],)=0.736,nm3, Vion([hftb],)=0.658,nm3, Vion([hfip],)=0.577,nm3) and their decomposition pathways in the mass spectrometric measurements have been established. The salts are highly soluble in non-polar solvents (up to 1.09,mol,L,1 are possible for [NBu4]+[hftb], in CH2Cl2 and 0.41,mol,L,1 for [NBu4]+[hfip], in CHCl3) and show higher molar conductivities if compared to [NBu4]+[PF6],. The electrochemical windows of CH2Cl2, CH3CN and 1,2-F2C6H4 using the [NBu4]+ aluminate electrolytes are up to +0.5,V/,0.7,V larger than those using the standard [NBu4]+[PF6],. [source] Rhombic Polyaniline Microsheets Constituted of Nanoparticles: Synthesis and Application to the Detection of DopamineCHINESE JOURNAL OF CHEMISTRY, Issue 3 2010Xiuhua Wang Abstract Rhombic polyaniline microsheets constituted of nanoparticles with the average diameter of 130 nm were synthesized and characterized by SEM, XRD and FTIR spectroscopy. A glassy carbon electrode modified with such rhombic polyaniline microsheets was fabricated and employed to detect dopamine via cyclic voltammetry, which displayed excellent electrochemical stability and sensitivity compared with the bare electrode. A linear relationship between the concentrations of dopamine and its oxidation peak currents was obtained. The proposed method was simple and economical in terms of the electrochemical method and apparatus. [source] | ||||||||||||||||